The present invention relates generally to dispensing apparatus for fluent products, and more particularly, to a hand-held gun for use in accurate dispensing of such fluent products.
By way of example, products which may be dispensed using the apparatus of the invention include so-called single component chemical foams, such as single-component urethane foams; various so-called silicone compositions, including silicone foams; caulking products such as acrylics, silicone-acrylic, silicone or other caulks and sealants; adhesives, such as those used in laminating or the like; and miscellaneous other products where a strip, bead or spray of the product is desired to be dispensed under careful control.
While the dispensing gun of the invention advantageously achieves its objects by including an attachment for an aerosol of like pressurized can, the gun is designed so that, with minimum modification, it may be fed from a cartridge or from a hose secured to the gun at one end and to a bulk container of a dispensable fluent product at the other end.
It is well-known that many products which may be stored and merchandised in cans and then dispensed therefrom are already satisfactory from a product standpoint. However, it is often difficult to dispense and apply such products to the satisfaction of the user, because of the manner in which the cans are pressurized and, more particularly, because the dispensing valves fixed to the cans are very inexpensive and not adapted for relatively precise dispensing. A great deal of skill is required to manipulate some such dispensing nozzles. Still others, regardless of the degree of care or skill applied, are simply designed to dispense products at a high rate or not at all.
The shape of the product container, normally a can, also often makes product application difficult. In particular, most relatively viscous products are dispensed with the can held in an inverted position, because of the nature of the contents and the pressurization system. This arrangement, plus the need to keep the body of the can away from the work area, results in an awkward position of the hands and fingers relative to the work site. The work site is often obscured by the can and attempting to manipulate the can while holding the same inverted and steady is a tedious task.
As a result, a number of adapters and the like have been proposed whereby cans may be associated with adaptor-dispenser and held away from the work. Such arrangements have, in some instances, provided improved visibility and ease of manipulation. However, most or all of such systems have suffered from the drawbacks of the dispensing gun valve. Thus, if there are inherent limitations in the dispensing mechanism, simply locating the can better or move conveniently will not improve the dispensing action. When such an action is inherently imprecise or undesirable, this aspect simply carries over to the dispensing apparatus.
Regarding dispensable fluent but viscous products, such as expanding and non-expanding chemical foams, including single component urethanes, caulks, and the like, several drawbacks have been encountered. First, the user often desires to lay down a rather narrow bead of material in one instance and a wider, higher bead in another instance. While bead size can sometimes be controlled when dispensing caulks from a caulking gun, the inherently intermittent nature of the manual trigger dispensing mechanism virtually guarantees a pulsating type delivery. Where a pressurized can is used, this aspect can be overcome but controlling bead size for one application and then later changing to another size, particularly a smaller size, is not possible, especially where the size is determined by cutting off the nozzle end. This applies equally to caulking tubes and guns. Regarding more fluent products, control of discharge consistent with acceptable dispensing rates is still a significant problem.
Certain prior art dispensers for single products have suffered from other drawbacks, including difficulties arising when a part of the valve component or other part of the dispensing mechanism was locked shut after a short period of non-use by the adhesive action of the material being dispensed. Almost all urethanes make excellent adhesives, but if the dispensing operation is intermittent, problems of undesired internal adhesions can arise as a result of allowing the apparatus to remain for a period of time when a component is filled with the foam or other product being dispensed.
In view of the above and other shortcomings in apparatus for dispensing viscous products, it is an object of the invention to provide an improved gun or the like for dispensing fluent products.
Another object of the invention is to provide an improved apparatus for dispensing more or less viscous products which are naturally adhesive in nature and which tend to clog dispensing apparatus.
A further object of the invention is to provide a dispensing gun which is able to provide a metering action for the product being dispensed and wherein the width or height of a bead of the dispensed product, or a spray pattern can be easily adjusted and maintained at a desired level.
A still further object of the invention is to provide a dispensing gun for fluent products which gun can be manufactured at extremely low cost, particularly in view of its advantages and characteristics.
Yet another object of the invention is to provide a gun which is adaptable, without material change, to dispense products either from bulk containers through attachment by a hose or the like, or to dispense products from an aerosol can or like container removably affixed to the gun.
Another object of the invention is to provide a gun with a novel valving arrangement for controlling flow of the products to be dispensed.
A further object of the invention is to provide a gun having a removable nozzle including an elongated central passage and an annular inner surface serving as a seat for a valving rod forming a part of the gun.
A still further object of the invention is to provide a valving system wherein two valves arranged in series are operated by a common mechanism, and in which the rate of dispensing or bead size of the product dispensed can be regulated by adjusting the position of the valves.
Yet another object of the invention is to provide a gun which includes a valving rod that may be easily rotated without tools, as by the fingers only, for example, relative to the nozzle within which it reciprocates, so as to free any adhesive connection which may have formed between the rod and the nozzle.
Another object of the invention is to provide a dispensing gun wherein manipulation of a valving rod can act to preset the size of the bead of material being dispensed.
A further object of the invention is to provide a valving arrangement in a dispensing gun whereby, with a proper setting of a pair of cooperating valves, a bead of material may be dispensed without the need for manipulating the gun trigger.
A still further object of the invention is to provide a novel valving arrangement including a rod, and a rod handle mechanism made at extremely low cost and cooperating with counterpart elements forming a part of the trigger mechanism.
Yet another object is to provide a dispensing gun having a handle, a center outlet passage and a first valve having a core, seating portion, a valve spring and a skirt surrounding the valve spring, with a rod extending through the valve core and into a removable nozzle having a reduced diameter outlet passage adapted to be closed off by the valving rod.
The foregoing and other objects and advantages the invention are achieved in practice by providing a novel dispensing gun having a body with product inlet and outlet passages, a removable nozzle affixed to the outlet passage, a trigger unit and a double valve arrangement actuated by the trigger and including a first valve having a reciprocable, seat-engaging nose portion movable in the product outlet passage between open and closed positions and a valving rod with a shank extending through the first valve, through a passage in the nozzle and having a free end closing off an inner tapered end portion of the nozzle.
The manner in which the foregoing and other objects and advantages of the invention are achieved in practice will become more clearly apparent when reference is made to the following detailed description of the preferred embodiments of the invention set forth by way of example and shown in the accompanying drawings, in which like reference numbers represent corresponding parts throughout.